The present invention relates to a shaping device for a soft extruded product. More especially, it concerns a device fitted to the extruder outlet to enable the linear flow of an extruded product in a soft state and to subject this product during its shaping in the required calibrated cross-section orifice to a cooling operation, or a hot vulcanizing operation, as well as an external surface smoothing in order to diminish as much as possible the surface friction to the product inside the orifice calibrated to the cross-section required and, moreover, to avoid any risk of the product sticking during its soft state to the inside wall of the calibrated orifice.
In the technique currently used to produce extrusions such as, for example, sections made from plastomer type plastic materials, it is necessary, immediately after the extrusion operation, to fix the cross-section of the section during the setting process in order to obtain the calibrated cross-section required. To do so, shaping devices are currently used, comprised of a single piece, designed to consume the necessary heat to obtain a viscous raw material and which enable vacuum to be used to apply the outside surface of the extruded section to the inner wall of the internal orifice in the shaping block which is calibrated to the cross-section required for the plastic section. This section cooling and shaping operation is performed during the continuous extrusion operation and certain problems of the section "sticking" to the calibrated orifice, during its soft state, frequently occur and constitute the main drawback with this type of shaping of the extruded product in the cooling phase.
The purpose of this invention is to provide a shaping device for linearly extruded products which eliminates the greater part of the drawbacks mentioned on single-piece devices such as are known to date and whose internal orifice for shaping of the product to the calibrated cross-section required may be adapted as required to the desired length by the addition of individual matrices positioned one after the other and each designed to enable the introduction of a gaseous fluid, at a temperature determined on the basis of the cooling or vulcanization operation chosen, in the direction of and on the outside of the extruded product to be shaped, and also a suction, in the direction of the matrix perimeter, of a gaseous fluid which has flowed round the product, the fluid circulation producing in each device, between the external surface of the product and the inner wall of the shaping orifice, a fluid layer flowing along the product in the extrusion direction and, consequently, preventing the product from sticking to and reducing its friction on the inner wall of the orifice whilst contributing to its smoothness and facilitating its flow to the exterior of the device outlet.